I own a Fisher Pulse 8x. It has a discriminator, but I never completely figured it out because it will still pick up junk. I did find a very nice brass prop, and an old hand gun from the 1950's with it. On that dive I was glad it picked up steel. In the early 90's I was on a S&R team and we had a similar unit. We found several guns with that unit also, mostly while searching for evidence. I mostly dive for fossils now, so I almost never use it anymore. I do recommend it because it is very durable.